Method of locking a handguard to an upper receiver of a firearm

ABSTRACT

A method of locking a handguard relative to an upper receiver of a firearm. The method includes providing a wedge assembly having a top wedge member and a bottom wedge member, each having complementary inclined surfaces; a barrel nut that is configured to receive an outer portion of an upper receiver; and a handguard that is configured to receive the barrel nut and the combined wedge assembly within a lower lip of the handguard. The wedge assembly may include an optional assembly screw and a locator pin where the top wedge member and bottom wedge member are tightly joined to each other via the assembly screw and the locater pin. In use, the lock-up system is used to join the handguard and barrel nut to a corresponding upper receiver with little to no play between the handguard and the upper receiver such that the connection between the two via the wedge assembly is intended to be permanent.

RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.14/502,702, filed Sep. 30, 2014, entitled “Lock Up System for aHandguard,” the contents of which are fully incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to a method of locking a handguard to anupper receiver of a firearm.

BACKGROUND OF THE INVENTION

Firearms, particularly high caliber rifles, are manufactured in variouscomponents, such as an upper receiver that includes a barrel nut and itscorresponding barrel extension, a barrel (discharge end), a boltcarrier, a lower receiver, a butt stock, a trigger, and a handguard.

Handguards are popular components of many firearms, particularly AR 15rifles and military M16s. Handguards extend over the firearm barrel andallow a firearm user to help align the barrel end of the firearm withouttouching a hot barrel after discharge. Further, handguards generallycontain a plurality of external openings in which accessories, likescopes and level devices, can be attached.

Handguards generally butt up to and are aligned with the upper receiver.It is desirable to have the connection between a handguard and itscorresponding upper receiver be as tight and permanent as possible.However, handguards do not always align end to end as desired and lockup with their corresponding upper receiver and there is resulting “play”between the two components. One option is to buy a one-piece upperreceiver/handguard, such as disclosed in U.S. Pat. No. 8,234,808 toLewis. But manufacturers and OEM manufacturers and some end users liketo buy separate handguards and assemble the handguard to the upperreceiver post-OEM or in the field. The current known locking systems arebulky in size, difficult to assemble, require laborious timing of theassembly to the upper receiver and can be difficult to remove forupdating and maintenance of the rifle.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to an innovative solution forproviding a lock-up device, a lock-up system that combines a handguardwith the lock-up device, and a method for near permanently joining ahandguard to a corresponding upper receiver via a barrel nut assemblyand the lock-up device.

According to one aspect of the present invention, the lock-up system isdirected to a handguard, a barrel nut, and a wedge assembly.

The handguard has a first end and a second end with a bore therethrough.The bore is configured to receive the barrel nut. The second end alsohas a lower lip that is adjacent to the bore. The lower lip has aninterior surface that is configured to receive the wedge assembly.

The barrel nut is configured to receive a barrel of a firearm. Thebarrel nut has a first end and a second end. The second end isconfigured to receive a portion of an upper receiver. The first end ofthe barrel nut has an outer surface that is configured to be receivedwithin the bore. The outer surface may be cylindrical in shape.

The wedge assembly includes a top wedge and a bottom wedge. The uppersurface of the top wedge has a generally indented surface, which may beconcave in shape. The generally indent surface of the top wedge isconfigured to be biased against the outer surface of the barrel nut. Thelower surface of the top wedge is inclined. The bottom wedge has a lowersurface configured to be received into and confront the interior portionof the lower lip of the handguard. The upper surface of the bottom wedgeis inclined, complementary to the incline of the lower surface of thetop wedge.

According to another aspect of the present invention, the lock-up systemis directed to a combined handguard, upper receiver, barrel nut, andwedge assembly. The barrel nut is affixed to a portion of the upperreceiver. Both the upper receiver and handguard have outer edges thatclosely confront each other in use. The upper receiver has a first endand a second end where the first end closely confronts the second end ofthe handguard with the barrel nut therebetween mostly positioned withinthe bore of the handguard. The locked-up handguard and upper receivermay look like a unitary member when assembled.

The lock-up system may include an optional assembly screw and locatorpin. The optional assembly screw is configured to be positioned within aslot of the inclined upper surface of the bottom wedge and a slot thatis abutted by a key in the lower inclined surface of the top wedge. Thescrew may be tightened to bring and retain the top and bottom wedgesinto close contact. The locator pin may be used to guide and retain therelative position of the top wedge relative to the bottom wedge. Thelocator pin is configured to be received within an aperture within thebottom wedge from the lower surface to the inclined surface.

Another embodiment includes a wedge assembly having an upper generallyindented surface and a lower inclined (angled) surface that isconfigured to be received within a complementary inclined (angled)interior surface of a lower lip of the handguard. The alternateembodiment wedge assembly may be unitary in construction.

Optional fastener or fasteners may be used to retain an exterior portionof the handguard relative to the inserted outer surface of the barrelnut.

The present invention also includes a method of locking-up a handguardrelative to a corresponding upper receiver. The method includesproviding a handguard configured as discussed above. A barrel nut, suchas described above is affixed to an external portion of the upperreceiver that has outer edges that conform to outer edges of the secondend of the handguard. The wedge assembly, as discussed above, ispositioned within the lower lip of the handguard with the respectiveinclined surfaces of the top and bottom wedge in a closely confrontingrelationship. The two inclined surfaces slide against each other toprovide tension and pressure. The bore and indented upper surface of thetop wedge, now combined and inserted within the lower lip of thehandguard, forms a hollow that conforms to the outer edge of the barrelnut. The barrel nut is squeezed into the hollow space between the uppersurface of the top wedge and within the bore. One or more fasteners maybe optionally added to secure the wedge to the handguard and the barrelnut outer surface to the handguard.

The method of locking-up the handguard relative to the correspondingupper receiver may include the alternate embodiment where the wedgeassembly is optionally unitary in nature so that the pressure ismaintained when the lower angled surface of the (preferably unitary)wedge assembly is inserted within a handguard that has a lower lipinterior surface that has a complementary angled surface to the lowerangled surface of the wedge assembly.

Similar to the system embodiments, the method may include tightening anoptional assembly screw, as well as an optional locator pin to providefurther tension and to tighten the bottom wedge to the top wedge.

Another optional feature is a partial aperture within each outer edge ofthe handguard and upper receiver, respectively. The partial aperture isaligned with the corresponding aperture of the other respective member(handguard or upper receiver). The combined entire aperture mayincorporate an alignment pin that aligns the upper receiver and thehandguard.

In this way, the physical connection between the wedge assembly,handguard, and barrel nut is secure and intended to be permanent.

These and other advantages are discussed and/or illustrated in moredetail in the DRAWINGS, the CLAIMS, and the DETAILED DESCRIPTION OF THEINVENTION.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, which are incorporated in and constitute apart of this specification, illustrate various exemplary embodiments.

Like reference numerals are used to designate like parts throughout theseveral view of the drawings, wherein:

FIG. 1 is an exploded perspective view of a lock-up system that caninclude a handguard, a barrel nut, and a lock-up device and where thelock-up device includes a top wedge member, a lower wedge member, and anoptional assembly screw and where the lock-up system is used topermanently join the handguard to a corresponding upper receiver and acorresponding barrel extension;

FIG. 2 is front assembled view of a combined wedge assembly, comprisingthe top wedge member, lower wedge member, and optional assembly screw ofFIG. 1;

FIG. 3 is a section view of the lock-up device taken along section lines3-3

FIG. 4 is a section view of a portion of the combined wedge assembly ofFIG. 2 positioned between the handguard and the barrel nut, which isreceived onto threads of the upper receiver of FIG. 1;

FIG. 5 is an unassembled perspective view of the combined wedgeassembly, the barrel nut, and a portion of the handguard;

FIG. 6 is a left end elevational view of the combined wedge assembly;

FIG. 7 is a front right end perspective view of the combined wedgeassembly;

FIG. 8 is an unassembled perspective view of the wedge assembly;

FIG. 9 is a right end elevational view of the combined wedge assemblyinserted into the handguard;

FIG. 10 is a right end elevational view of an alternate embodiment wedgeassembly inserted into a handguard;

FIG. 11 is a front section view of an assembled handguard, barrel nut,and alternate embodiment combined wedge assembly taken substantiallyacross lines 11-11 of FIG. 10;

FIG. 12 is an exploded perspective view of the handguard, barrel nut,and alternate embodiment combined wedge assembly; and

FIG. 13 is a rear section view of the assembled handguard, barrel nut,and alternate embodiment of FIG. 11.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-9, according to one embodiment of the invention,the lock-up system of the present invention consists of a handguard 1, abottom wedge 2, a locator pin 3, a top wedge 4, an assembly screw 5, anda barrel nut 6. The lock-up system is designed to attach to any milspecupper receiver 8 and barrel extension 7, illustrated in FIG. 1.

Locator pin 3 is pressed into a hole 101 of bottom wedge 2 such that adiameter 102 of locator pin 3 protrudes from a lower surface 103 ofbottom wedge 2, but not into a slot 104. Assembly screw 5 is insertedinto a threaded a hole 105 of top wedge 4 such that a diameter 106 ofassembly screw 5 engages an elongated diameter 107 of top wedge 4. Topwedge 4 and assembly screw 5 now engage bottom wedge 2 with assembledlocator pin 3 such that an inclined (angled) surface 108 of the bottomwedge 2, and a complementary inclined (angled) surface 109 of the topwedge 4 are in direct contact, and a key 110 of top wedge 4 correspondsto and is positioned within slot 104 of bottom wedge 2. Further,assembly screw diameter 106 is captured within a cutout 111 of bottomwedge 2.

Referring to FIG. 2, the inclined surface of the bottom wedge may be anangle a in the range of 0.5 to 85 degrees, with a preferred range of 1.5to 4 degrees as measured from an imaginary plane P-P. The top wedge'scomplementary inclined surface angle would be in the range of 0.5 to 85degrees, with a preferred range of 1.5 to 4 degrees as measured from animaginary plane P₁-P₁. According to one aspect of the present invention,the angle of the inclined lower surface of the top wedge and the angleof the inclined upper surface of the bottom wedge are equal orsubstantially so that the overall profile of the combined wedge assemblyis generally rectangular in shape.

Referring particularly to FIGS. 4 and 5, the complete wedge assembly(FIGS. 2 and 3) with bottom wedge 2, top wedge 4, locator pin 3, andassembly screw 5 can now be assembled into handguard 1. The assemblyaligns by locating diameter 102 of locator pin 3 into an opening 112 ofhandguard 1. Lower surface 103 of bottom wedge 2 seats into a lower lip115 of handguard 1. Lower lip 115 defines an interior slot 113 that isaccessed through an opening of the handguard. A flat front 114 of topwedge 4 is brought into close proximity of slot 113/opening of handguard1.

In use, barrel nut 6 will be fastened onto upper receiver 8 by threads116 of the barrel nut 6 and threads 117 of the upper receiver 8, therebyholding the barrel extension 7 in place along with any firearm barrelreceived therein. Holding the wedge assembly (FIG. 2) into position, awrench may be inserted through opening 118 in the handguard 1, therebyadjusting the assembly screw 5. By turning the assembly screw in aclockwise direction, the screw threads 119 are drawn into the threadedhole 105 of the top wedge 4. As this proceeds, the screw head surface120 contacts the capture surface 121 of the bottom wedge 2 in such a wayas to impede movement of said screw, independent of the bottom wedge 2,Since the assembly screw can move no further, being stopped against thecapture surface 121 on the bottom wedge 2, further clockwise rotation ofthe assembly screw 5 results in motion of the top wedge 4 toward thesurface 120 of the assembly screw.

The two wedges are held in constant contact by an assembler, causing thesurface 108 of the bottom wedge 2 and the surface 109 of the top wedge 4to be held in contact. The motion of the top wedge 4, relative to thebottom wedge 2, commences when assembly screw 5 is turned clockwise. Asthe smallest ends of each wedge move toward each other, a generallyindented, preferably concave, surface 122 of the top wedge 4 moves intocloser proximity of the lower surface 103 of the bottom wedge 2. Ingeneral, this means that the concave surface 122 of the top wedge 4 isreceding from the open diameter 123 of the handguard 1. As thisloosening of the wedge continues, the top wedge 4 moves in such a way asto bring its forward surface 114 into contact with the interior surfaceof lower lip 115 of the handguard 1. A small amount of pressure can becreated between these two surfaces(surface 114 and interior surface oflower lip 115) by continuing to rotate the assembly screw 5 clockwise afew degrees beyond the point wherein the surface 114 and the interiorsurface of lower lip 115 are brought into contact causing the wedge toseat itself open and held in position for assembly and confrontationwith the barrel nut 6. At this time, an assembler releases hold of thewedge assembly (FIG. 2), as it is now self-retained.

With the conditions described it is now possible to slide the handguard1 with wedge assembly (FIG. 2) over the barrel nut 6, which is threadedonto the threaded end of upper receiver 8. The handguard diameter 123,which is fashioned to be slightly larger than the diameter 124 of thebarrel nut 6, together with the wedge assembly surface 122, now forms arelative (e.g., cylindrical) hollow that corresponds to the outersurface diameter) 124 of the barrel nut 6. The handguard 1, incombination with the wedge assembly (FIG. 2), now slides onto the barrelnut 6 until confronting contact is made between the handguard 1 and theupper receiver 8 along their respective flat outer edges (125, 126 ofFIGS. 1 and 4). Some form of alignment may be made at this time, suchthat the addition of an alignment pin 133 extending between aperture 127and corresponding aperture 128 of the upper receiver 8 and handguard 1,respectively.

Once confronting contact is made between the upper receiver 8 and thehandguard 1, a wrench may be once again inserted through the handguardopening 118 to access assembly screw 5. By rotating the screwcounter-clockwise, a relatively small reverse in the motion of thewedges 2, 4 may be achieved when the surface 129 of assembly screw 5 andthe capture surface 130 of bottom wedge 2 make contact. Now the assemblyscrew 5 will not move independent of the bottom wedge 2 as a result ofthese two surfaces making confrontational contact. The threaded portionof the top wedge 4 will move away from the head of said screw and downthe length of the assembly screw's threaded portion 119. The relativemotion of the two wedges results in the larger ends of each wedge movingcloser to each other. Concave upper surface 122 of top wedge 4 and lowersurface 103 of bottom wedge 2 move away from each other. As thishappens, the concave surface has already been put into biasing contactwith the cylindrical diameter 124 of barrel nut 6 as the concave uppersurface 122 of top wedge 4 moves toward the relative center of thediameter 123 of handguard 1. A squeezing force is applied to the outerdiameter 124 of the barrel nut 6. This squeezing force between thehandguard inner diameter 123 and the concave upper surface 122 of topwedge 4 that is applied to the outer diameter 124 of the barrel nut 6affixes the handguard to the barrel nut, holding the relationshipbetween the handguard 1 and the upper receiver 8 near permanently.

Once the attachment is completed further fasteners can be applied ifdesired. Two threaded holes 131 are applied to the sides of thehandguard 1 in such a way as to be related to the diameter 123 near themiddle of the features' longitudinal length. Two set screws can bethreaded into these holes such that they protrude into the innerdiameter 123 of the handguard 1 and intersect a radial cut 132 of thebarrel nut 6. The radial cut 132 of barrel nut 6 is angled back towardthe upper receiver 8. As these set screws are tightened into the radialgroove 132, they tend to slide down its angle, being forced toward upperreceiver 8. The result is that handguard 1 is forced toward the upperreceiver 8. No further movement of the handguard toward the upperreceiver is possible as the two outer edges 125, 126 of handguard 1 andupper receiver 8, respectively, are already in confronting contact witheach other. This additional force has the added benefit of resisting anypossible movement of the handguard 1 off of the barrel nut 6.

There are many possible methods of employing wedge surfaces to achievehandguard lock-up of a handguard to a receiver. Above described is aserviceable design and method to achieve this end, but many variationsof the wedge surface, its angle, shape, location, and interrelationshipto the handguard, barrel nut, and receiver can be created.

Many possible permutations of the invention exist. One such permutationis an alternate embodiment illustrated in FIGS. 10-13.

In this embodiment, handguard 11, which is substantially the same ashandguard 1, is brought into contact with barrel nut 12 alongcylindrical surface 201 of barrel nut 12 and cylindrical surface 202 ofhandguard 11. Handguard 11 has a first end and a second end with a bore210 therebetween. Similar to the first embodiment, handguard 11 has alower lip 17 with an interior surface 209 that is configured to receivea wedge assembly 16 via end 206 of wedge assembly 16,

Barrel nut 12 is substantially the same as barrel nut 6 in the firstembodiment. Barrel nut 12 has a first end and a second end where thefirst end is configured to receive a portion of an upper receiver (notillustrated in FIGS. 10-13) and a second end has an outer surface (e.g.,a cylindrical surface) 201 that is configured to be received axiallywithin bore 210 of the handguard and directly above the lower lip. Theinterior surface of the lower lip has an inclined surface or surfaces205 that is complementary to the lower surface(s) 204 of wedge assembly16.

The wedge assembly 16 in this embodiment is different in that it doesnot need an assembly screw, a key/slot combination, or a locator pin.Rather, the wedge assembly has an upper generally indented (e.g.,concave) surface 203 and an inclined lower surface 204 that iscomplementary to the inclined surface 205 of handguard 11. The angles ofthe inclined surfaces 205 (handguard) and wedge lower surface 204 may bein the same general angled ranges as those discussed in the firstembodiment.

Concave surface 203 is placed in near contact with cylindrical surface201 of barrel nut 12, and inclined surface or surfaces 204 of wedgeassembly 16 are simultaneously brought into contact with inclinedsurface or surfaces 205 of handguard 11 lower lip 17. In this case, endsurface 206 of wedge assembly 16 would begin in its loosened conditionin near or exact contact with abutting surface 207 of handguard 11. Asassembly proceeds, opposite end surface 208 of wedge assembly 16 wouldmove rearward toward leading edge surface 209 of handguard 11. As thisaction continues, wedge assembly 16 slides across the contact betweenits inclined surfaces 204 and the inclined surfaces 205 of handguard 11,causing generally indented (e.g., concave) surface 203 to approach,contact and then pressure the outer (e.g., cylindrical) surface 201 ofbarrel nut 12. This pressure exerted effectively causes lock-up of thehandguard, wedge and barrel nut.

The present invention may include other variants such as a tapered pinand conical slot as an alternate to the first embodiment. In such avariant, the slot would exist in both the barrel nut and handguard, towhich the tapered pin could be applied to bring about said wedgepressure to cause handguard to receiver lock-up.

These few examples and embodiments, which are by no means exhaustive,are merely intended to illustrate some of the many variations that canoccur without departing from the spirit of the invention.

Therefore it is the Applicant's intention that its patent rights not belimited by the particular embodiments illustrated and described herein,but rather by the following claims interpreted according to accepteddoctrines of claim interpretation, including the Doctrine of Equivalentsand Reversal of Parts.

1. A method of locking a handguard of a firearm to a corresponding upperreceiver; the method comprising: providing an upper receiver of afirearm having a first end and a second end; the first end having outeredges and an outwardly extending threaded portion; providing a handguardhaving a first end and a second end with a bore therebetween; the secondend having outer edges that are configured to closely confront the outeredges of the upper receiver; the bore is configured to receive theoutwardly extending threaded portion of the upper receiver; thehandguard further configured to include a lower lip at the first end,the lower lip having an interior surface; providing a barrel nut havinga first end and a second end, said second end configured to receive theoutwardly extending threaded portion of the upper receiver and the firstend configured to receive a barrel of a firearm; the barrel nut havingan outer surface at the first end; providing a wedge assembly having atop wedge with an upper generally indented surface and a lower inclinedsurface, and a bottom wedge with an upper inclined surface inverselycomplementary to the inclined surface of the top wedge and a lowersurface configured to be received and confront the interior surface ofthe lower lip of the handguard; securing the second end of the barrelnut to the threaded portion of the upper receiver; sliding the top wedgeinto contact with the bottom wedge at their respective inclined surfacesand joining the wedge assembly together to form a combined wedgeassembly where the two respective inclined surfaces are closelyconfronting each other; positioning the combined wedge assembly withinthe interior portion of the lower lip of the handguard with the upperindented surface of the top wedge forming a hollow that is configured toclosely receive the outer surface of the barrel nut; squeezing the outersurface of the barrel nut into the hollow of the handguard; and aligningand confronting the two outer edges of the handguard and upper receiver.2. The method according to claim I wherein the outer edges of therespective upper receiver and handguard each include a complementaryportion of an aperture that is configured to form one unitary apertureand receive an alignment pin when the two outer surfaces are broughtinto confronting contact with each other.
 3. The method according toclaim 1 wherein the generally indented upper surface of the top wedge isconcave in shape and the outer surface of the barrel nut is cylindricalin shape.
 4. The method according to claim 1 wherein the wedge assemblyfurther comprises an assembly screw that is configured to be receivedwithin a slot of the bottom wedge within the inclined surface and drawninto a threaded hole of the top wedge; and wherein the assembly screw istightened to tightly join the top wedge to the bottom wedge.
 5. Themethod according to claim 4 wherein a locator pin is secured into anaperture of the lower surface of the bottom wedge generallyperpendicularly to the slot of the bottom wedge.
 6. The method accordingto claim 1 wherein one or more fasteners are inserted within an outerwall of the handguard to further secure the outer surface of the barrelnut to the handguard.
 7. A method of near permanently joining ahandguard firearm to a corresponding upper receiver; the methodcomprising: providing an upper receiver of a firearm having a first endand a second end; the first end having outer edges and an outwardlyextending threaded portion; providing a handguard having a first end anda second end with a bore therebetween; the second end having outer edgesthat are configured to closely confront the outer edges of the upperreceiver; the bore is configured to receive the outwardly extendingthreaded portion of the upper receiver; the handguard further configuredto include a lower lip at the first end, the lower lip having an angledinterior surface; providing a barrel nut having a first end and a secondend, said second end configured to receive the outwardly extendingthreaded portion of the upper receiver and the first end configured toreceive a barrel of a firearm; the barrel nut having an outer surface atthe first end; providing a wedge assembly having an upper generallyindented surface and a lower angled surface configured to be receivedand confront the angled interior surface of the lower lip of thehandguard; securing the second end of the barrel nut to the threadedportion of the upper receiver; sliding the wedge into contact with theangled interior surface of the lower lip of the handguard where the tworespective angled surfaces closely confront each other; positioning theassembly within the lower lip of the handguard with the upper indentedsurface of the wedge forming a hollow that is configured to closelyreceive the outer surface of the barrel nut; squeezing the outer surfaceof the barrel nut into the hollow of the handguard; and aligning andconfronting the two outer edges of the handguard and upper receiver.